Bulletin of the American Physical Society
2020 Fall Meeting of the APS Division of Nuclear Physics
Volume 65, Number 12
Thursday–Sunday, October 29–November 1 2020; Time Zone: Central Time, USA
Session EJ: Undergraduate Research I |
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Chair: Shelly Lesher |
Friday, October 30, 2020 10:30AM - 10:42AM |
EJ.00001: Mapping the 3D Structure of Hadrons through Asymmetries in Single-Inclusive Pion Production from Electron-Proton Collisions Michel Malda, Joshua Miller, Daniel Pitonyak, Alexei Prokudin, Nobuo Sato By utilizing high-energy single-spin asymmetry data, researchers are able to map and understand the 3D structure of hadrons. However, for single-inclusive processes these studies mostly analyze the observable $A_{N} $in proton-proton collisions at RHIC, which operates at $\surd $S $=$ 200 GeV in the forward region. HERMES and JLab provide data for lower-energy electron-proton collisions in the backward region. By using the results from a recent global analysis, we are interested in comparing to existing data and making predictions for the Electron-Ion Collider. We implemented hadronic mass corrections (HMC) for fixed-target experiments and analyzed separately the Collins-type and Sivers-type functions.~The HMC seem to have little impact on the asymmetry, whereas studying the Collins-type and Sivers-type terms gave insight into the hard factors and functions that play the largest role in describing the asymmetry data. EIC kinematics prove to be very sensitive to the extractions of the Collins-type and Sivers-type functions from single-spin asymmetries. With global fits including EIC data we will gain a greater understanding of these observables and the 3D structure of hadrons. [Preview Abstract] |
Friday, October 30, 2020 10:42AM - 10:54AM |
EJ.00002: Transverse momenta and flow coefficients from modeled Xe Xe collisions using hic-eventgen Nicholas Summerfield, Anthony Timmins The quark-gluon plasma (QGP) is a state of hadronic matter that is created at extremely large temperatures and pressures. It can be created in the laboratory through relativistic heavy ion collisions, and only for an unobservable instant before freezing into hadrons. To study the properties of the QGP, hydrodynamic models are employed to recreate such events that follow a collision up to the point of detection. In this research, we will utilize the hic-eventgen chain, which models heavy-ion collisions using initial conditions from T$_{\rm R}$ENTo, VISHNu 2+1 hydrodynamics, and UrQMD for the hadronic afterburner. The input parameters (e.g. the shear and bulk viscosities divided by the entropy density) for this chain have been tuned to describe the measured average transverse momenta and flow coefficients in Pb-Pb collisions at both $\sqrt{s_{\rm{NN}}}$ = 2.76 GeV and 5.02 GeV using a Bayesian analysis. We will use these tuned parameters to test whether the hic-eventgen chain can describe measurements of average transverse momenta and flow coefficients from Xe-Xe collisions at $\sqrt{s_{\rm{NN}}}$ = 5.44 GeV. [Preview Abstract] |
Friday, October 30, 2020 10:54AM - 11:06AM |
EJ.00003: Studies of the continuum region in the $^{\mathrm{4}}$He(e,e'p)X reaction Aiden Boyer, Fatiha Benmokhtar Helium-4 is the lightest nucleus that has the characteristics of heavier nuclei. The E08009 experiment in hall A at Jefferson lab aims to study the behavior of the proton inside this nucleus. This is possible through the study of the $^{\mathrm{4}}$He(e,e'p)X reaction. My work was on data analysis and the extraction of the missing energy spectra up to the pion threshold. The cleaning of the spectra was done by the study the Physics acceptance that takes into account the geometrical phase-pace and target length reconstruction as well as spectrometer momentum resolution. In addition, coincidence events were validated by selecting a time window of 20 ns for the difference of the arrival time of electrons and protons. Cross section results for the 2 body breakup channel have been extracted and I am extending the method to the continuum channel. From this study, we will learn how the knocked out proton interacted inside the nucleus with its counterparts protons and neutrons. [Preview Abstract] |
Friday, October 30, 2020 11:06AM - 11:18AM |
EJ.00004: Invariant yield and nuclear modification factor of the $\phi$ meson in p+Al, p+Au, and $^3$He+Au collisions of systems at $\sqrt{s_{NN}}$ = 200 GeV James Shirk The measurement of $\phi$ mesons provides a unique and complementary method for exploring properties of the quark-gluon plasma (QGP). The $\phi$ meson has a relatively small hadronic interaction cross section and is sensitive to the increase of strangeness in the QGP (strangeness enhancement), a phenomenon associated with soft particles in bulk matter. Measurements in the dilepton channels are especially useful since leptons interact only electromagnetically, thus carrying the information about their production directly to the detector. Measurements in different nucleus-nucleus collisions allow us to perform a systematic study of the nuclear medium effects on $\phi$ meson production and gain better insight to the formation of the QGP. With data taken by the PHENIX detector in 2014 and 2015, we measure the $\phi$ meson production in a wide range of transverse momenta and rapidity. In this talk, we present the status of $\phi$ meson invariant yield and nuclear modification ($R_{AA}$) measurements in a variety of small collision systems, including p+Al, p+Au, and $^3$He+Au at $\sqrt{s_{NN}}$ = 200 GeV. The data are compared with the AMPT "A Multi-Phase Transport" model. [Preview Abstract] |
Friday, October 30, 2020 11:18AM - 11:30AM |
EJ.00005: Angular Power Spectrum in Heavy Ion Collisions from Simulations Hannah Anderson, Shengquan Tuo The pixelization code HEALPix was created by the Jet Propulsion Laboratory to analyze the cosmic microwave background. As has been shown using public data from the ALICE experiment, its two-dimensional representation of a sphere containing pixels of equal area has a broader application to heavy ion collisions. The application of HEALPix includes the concept of the angular power spectrum which details the contribution of spherical harmonics to the distribution of particles over the detector. This angular power spectrum can be directly related to the density and distribution of particles, which in turn relates to the particle flow. Through the use of simulated heavy ion data, we explore different aspects of the angular power spectrum and how it relates to flow analysis. There are some important details not covered within this study, such as the influence of non-flow. Therefore, the influence of non-flow is discussed in relation to the flow analysis. The angular power spectrum and features within the odd modes are detailed along with their specific application in heavy ion collisions. Through this study, it has become clear that HEALPix is another viable tool to be used in heavy ion flow analysis. [Preview Abstract] |
Friday, October 30, 2020 11:30AM - 11:42AM |
EJ.00006: Trace Fitting of a Charged Particle Telescope to use with MoNA Georgia Votta, Nathan Frank, Thomas Baumann, Paul Gueye, Thomas Redpath, Belen Monteagudo Godoy, Anthony Kuchera Measurements of neutron-unbound states in nuclides typically assume that the resulting charged fragment after neutron emission will be in a bound ground state. This may not always be the case, so a compact charged particle detector telescope~composed of five Si detectors and one CsI calorimeter~has been developed~by the MoNA Collaboration~to enable a gamma-ray detection array to be placed around it~for~unequivocally~identifying~bound excited~states. These experiments require radioactive beams so this device will be used at the National Superconducting Cyclotron Laboratory on the campus of Michigan State University. A test-run~with this telescope~was performed~at the NSCL~in January of~2020 using a digital data acquisition system. Traces from each detector were recorded during the run and are being analyzed~to assess the performance of the device. This presentation will focus on the progress in this work. [Preview Abstract] |
Friday, October 30, 2020 11:42AM - 11:54AM |
EJ.00007: Advancing Few-Body Methods for Nuclear Reactions Simon Sundberg \par Nuclear Physics was established with Rutherford's scattering experiment which used an alpha-beam to study nuclei. Today similar scattering reactions are used to study unstable nuclei structure. Given the wide range of applications of nuclear physics across the scientific landscape including energy, medicine, agriculture, astrophysics and more, it is important to have a robust theoretical framework for reactions. \par Some important reactions beyond elastic scattering include breakup (where the incoming projectile nucleus breaks up in two or more fragments) and transfer (where a nucleon or nucleon cluster is transferred between the projectile and the target). If the degrees of freedom of a system allow it, an effective few-body model can be used. Our group is interested in deuteron induced reactions which can be mapped onto a three-body problem with neutron+proton+nucleus. \par We introduce several few-body techniques used to study reactions and their connection to nuclear structure. Specific applications will be shown using the Faddeev approach, since this framework offers exact solutions to the nuclear scattering problem. An accessible discussion of this method will be provided, as well as an overview of new developments in the pipeline. [Preview Abstract] |
Friday, October 30, 2020 11:54AM - 12:06PM |
EJ.00008: Determining the charge sharing bias between pixels in Nab silicon detectors Madeline Copeland, Leah Broussard Precise measurements of the electron-neutrino correlation coefficient and the Fierz interference term in unpolarized free neutron beta decay are performed by the Nab and the Calcium-45 experiments for testing our understanding of the Standard Model's description of the weak interaction. These experiments use silicon detectors, segmented into hexagonal pixels, that collect the total charge deposited by the decay particles. We updated custom Fortran code to simulate charge collection in Nab silicon detectors using the Shockley-Ramo theorem. To study if the detectors accurately collect the total charge deposited, simulated waveforms were created based on the input energy of decay particles and simulated characteristics of Nab detectors. We studied the simulated waveforms' amplitude and shape dependence on the electron energy and position, focusing on the effect of charge sharing among the pixels. A change in the waveform shape can result in a bias in the detected energy due to charge sharing. We also studied the impact on low energy proton detection efficiency near pixel boundaries due to charge sharing. Ultimately, investigating charge sharing will aid the Nab Experiment and the Calcium-45 Experiment to set a limit on the size of the Fierz interference term. [Preview Abstract] |
Friday, October 30, 2020 12:06PM - 12:18PM |
EJ.00009: GEANT4 Simulation Study of Light Collection Performance from Plastic Scintillating Tiles Zachary Langford In recent years, there has been an increase in the popularity of using silicon photomultipliers (SiPM) for light collection from scintillators in particle detectors. The members of the high energy nuclear physics group at Georgia State University are testing over twelve thousands plastic scintillating tiles in 24 shapes with variable sizes and routing patterns of wavelength shifting fibers. These tiles are used for building the sPHENIX Hadronic Calorimeter for particle jet energy measurement in heavy ion collisions at the Relativistic Heavy Ion Collider at Brookhaven National Lab. In order to quantify the light collection uniformity and efficiency of these scintillating tiles with different fiber routing patterns, a GEANT4-based simulation has been developed. In this presentation, we highlight the important steps of constructing the optical components in the simulation and show the preliminary results from our studies. [Preview Abstract] |
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